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Satellite to Satellite communication ?



 
 
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  #1  
Old December 7th 03, 08:37 PM
Norris Watkins
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Posts: n/a
Default Satellite to Satellite communication ?

Hello:
1. When you make an international phone call - say from NY to China -
how does the voice data travel ? Does it have to be send to the
satellite and then received at teh ground, some distance away, then
sent to another satellite till it reaches the destination country. ? I
mean is there any direct satellite to satellite communication. Or is
it always bouncing between teh satellite and the ground at an angle.

2. Is this true for international television programming too ? I know
there are live television from Arab countries, Japan etc, in US.

Thanks
--sony
  #4  
Old December 8th 03, 01:07 AM
Ken Taylor
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Default Satellite to Satellite communication ?

"Norris Watkins" wrote in message
om...
Hello:
1. When you make an international phone call - say from NY to China -
how does the voice data travel ? Does it have to be send to the
satellite and then received at teh ground, some distance away, then
sent to another satellite till it reaches the destination country. ? I
mean is there any direct satellite to satellite communication. Or is
it always bouncing between teh satellite and the ground at an angle.

2. Is this true for international television programming too ? I know
there are live television from Arab countries, Japan etc, in US.

Thanks
--sony


The satellites in question are at an orbit 35,000km above the earth and can
'see' a large portion of the Earth's surface. Two ground stations on
separate continents can both see the same satellite if it is correctly
located, and so they can pass a call between them. Hence USA-Europe,
USA-Asia and so forth is possible in one 'hop'. Satellite to satellite can
be done, as in the Iridium system, but I don't know of any other system
off-hand which is commercial and made it to service. There's generally not
actually a need.

Ken


  #5  
Old December 8th 03, 01:07 AM
Ken Taylor
external usenet poster
 
Posts: n/a
Default Satellite to Satellite communication ?

"Norris Watkins" wrote in message
om...
Hello:
1. When you make an international phone call - say from NY to China -
how does the voice data travel ? Does it have to be send to the
satellite and then received at teh ground, some distance away, then
sent to another satellite till it reaches the destination country. ? I
mean is there any direct satellite to satellite communication. Or is
it always bouncing between teh satellite and the ground at an angle.

2. Is this true for international television programming too ? I know
there are live television from Arab countries, Japan etc, in US.

Thanks
--sony


The satellites in question are at an orbit 35,000km above the earth and can
'see' a large portion of the Earth's surface. Two ground stations on
separate continents can both see the same satellite if it is correctly
located, and so they can pass a call between them. Hence USA-Europe,
USA-Asia and so forth is possible in one 'hop'. Satellite to satellite can
be done, as in the Iridium system, but I don't know of any other system
off-hand which is commercial and made it to service. There's generally not
actually a need.

Ken


  #6  
Old December 8th 03, 01:54 AM
Joann Evans
external usenet poster
 
Posts: n/a
Default Satellite to Satellite communication ?

Norris Watkins wrote:

Hello:
1. When you make an international phone call - say from NY to China -
how does the voice data travel ? Does it have to be send to the
satellite and then received at teh ground, some distance away, then
sent to another satellite till it reaches the destination country. ? I
mean is there any direct satellite to satellite communication. Or is
it always bouncing between teh satellite and the ground at an angle.

2. Is this true for international television programming too ? I know
there are live television from Arab countries, Japan etc, in US.

Thanks
--sony


Sometimes there are *multiple* satellite hops, depending.

For a one-way broadcast, it doesn't matter much, but a few years ago,
I had occasion to watch a Presidential address where multiple
televisions were present, and tuned each to a different network. No two
were in sync, implying different speed of light delays between the point
of origin in Washington D.C., and the local stations.

Then there's the noticeable delay on a news program when the anchor
is in 'live' contact (espically with videophones) with the reporter in
the field....


--

You know what to remove, to reply....
  #7  
Old December 8th 03, 01:54 AM
Joann Evans
external usenet poster
 
Posts: n/a
Default Satellite to Satellite communication ?

Norris Watkins wrote:

Hello:
1. When you make an international phone call - say from NY to China -
how does the voice data travel ? Does it have to be send to the
satellite and then received at teh ground, some distance away, then
sent to another satellite till it reaches the destination country. ? I
mean is there any direct satellite to satellite communication. Or is
it always bouncing between teh satellite and the ground at an angle.

2. Is this true for international television programming too ? I know
there are live television from Arab countries, Japan etc, in US.

Thanks
--sony


Sometimes there are *multiple* satellite hops, depending.

For a one-way broadcast, it doesn't matter much, but a few years ago,
I had occasion to watch a Presidential address where multiple
televisions were present, and tuned each to a different network. No two
were in sync, implying different speed of light delays between the point
of origin in Washington D.C., and the local stations.

Then there's the noticeable delay on a news program when the anchor
is in 'live' contact (espically with videophones) with the reporter in
the field....


--

You know what to remove, to reply....
  #8  
Old December 8th 03, 05:09 AM
Greg D. Moore \(Strider\)
external usenet poster
 
Posts: n/a
Default Satellite to Satellite communication ?


"Norris Watkins" wrote in message
om...
Hello:
1. When you make an international phone call - say from NY to China -
how does the voice data travel ? Does it have to be send to the
satellite and then received at teh ground, some distance away, then
sent to another satellite till it reaches the destination country. ? I
mean is there any direct satellite to satellite communication. Or is
it always bouncing between teh satellite and the ground at an angle.


Generally ground to sat to ground and that's it.

Sat to sat communication is fairly rare.


2. Is this true for international television programming too ? I know
there are live television from Arab countries, Japan etc, in US.

Thanks
--sony


  #9  
Old December 8th 03, 05:09 AM
Greg D. Moore \(Strider\)
external usenet poster
 
Posts: n/a
Default Satellite to Satellite communication ?


"Norris Watkins" wrote in message
om...
Hello:
1. When you make an international phone call - say from NY to China -
how does the voice data travel ? Does it have to be send to the
satellite and then received at teh ground, some distance away, then
sent to another satellite till it reaches the destination country. ? I
mean is there any direct satellite to satellite communication. Or is
it always bouncing between teh satellite and the ground at an angle.


Generally ground to sat to ground and that's it.

Sat to sat communication is fairly rare.


2. Is this true for international television programming too ? I know
there are live television from Arab countries, Japan etc, in US.

Thanks
--sony


 




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